Trifid and tetrafid renal sinus: A rare anatomical variation present in a pediatric patient

Abstract

Introduction. The anatomical variations of the renal sinus appear as hyperechoic areas on ultrasonography, which may be misinterpreted as true hyperechoic masses like renal angiomyolipomas. Case report. A 10-year-old girl was referred to a tertiary children’s hospital due to suspected bilateral renal angiomyolipomas. Upon admission, laboratory test results were within normal reference ranges. Ultrasonographic examination revealed that both kidneys had a normal position and size. On the sagittal ultrasound scan of the right kidney, three columnar masses extending across the sinus were observed, creating the appearance of three hyperechoic zones, indicating a trifid renal sinus. On the sagittal ultrasound scan of the left kidney, multiple columnar masses extending across the sinus were observed, creating the appearance of four hyperechoic zones, identified as a tetrafid renal sinus. The findings were interpreted as a rare benign anatomical variation with no signs of pathology, and additional radiological imaging was not required. Conclusion. Accurate identification of these variations is crucial to prevent patients from undergoing unnecessary biopsies and additional imaging.